Police are investigating the London Fire Brigade's use of a "stay put" policy while dozens of firefighters battled the Grenfell Tower inferno.

Residents became trapped as flames quickly spread from floor to floor and they were advised to stay in their flats shortly after the fire was reported.

The Metropolitan Police is considering possible health and safety offences as part of its criminal probe into the disaster which left 72 people dead.

The LFB has been criticised for the length of time taken to abandon the policy - nearly two hours after the blaze was first reported in the early hours of June 14 last year - despite flames reaching every floor.

Detective Superintendent Matt Bonner said the policy was part of investigators' "assessment of what happened and therefore falls within the investigation".

Commander Stuart Cundy clarified that the force was "duty bound" to look at a broad range of aspects from the night, which included the emergency services' response and preparedness.

Asked if senior officers could be charged with manslaughter for not telling people to leave, Mr Bonner said a prosecution could most likely fall under health and safety legislation.

Inside the fourth floor flat where the blaze broke out (Image: Handout)

He said: "The LFB would, as any other organisation involved, have an obligation to conduct their activity in a manner that doesn't place people at risk. It doesn't mean that at the moment they have or they haven't, but that's where the legislation is most likely to arise if that was an eventuality."

An inquiry into the tragedy heard fire commanders marshalling the battle against the inferno had "no obvious and safe alternative strategy" than telling residents of the 24-storey block in Kensington, west London to stay put.

On the final day of opening statements at the inquiry into the disaster, the Fire Brigades Union (FBU) said both commanders and firefighters were left in an "impossible situation".

The refurbishment of the building has seen material installed that made it a "highly combustible death trap", which the brigade lacked training and procedures to tackle, the union said.

Banners have been unveiled on the tower ahead of the one-year anniversary of the tragedy (Image: PA)

Fire safety advice within tall buildings is set by the building owners, not the fire service, meaning it accords with the design specifications and escape capabilities.

Stephen Walsh QC, representing the LFB, told the inquiry: "It is a fundamental misunderstanding of the events of the fire and of fire service capability to assume the building's stay-put policy can be changed to a simultaneous evacuation at the stroke of a fire incident commander at whatever time."

"If there is no policy applied by the building owner which provides for a policy of simultaneous evacuation and there are no evacuation plans and there are no general fire alarms - what is an incident commander on the fireground to do?"

Martin Seaward, for the FBU, used his opening statement to ask "what alternative strategy might have been implemented" in the fast-moving situation.

The unburned lower floors with untouched cladding still in place (Image: AFP)

An unprecedented number of firefighters with breathing apparatus entered the burning tower, Mr Walsh said.

He added: "Firefighters carried out many rescues of residents from flats and assisted many others that they encountered elsewhere in the building to make their escape down the stairs."

Many were left in "intolerable positions" and were forced to make decisions with "serious consequences whatever they decided to do", he said.

People comfort each other at a vigil following the fire last year (Image: Getty)

Both call operators and firefighters on the scene still suffer from the physical and emotional repercussions of responding to the disaster, Mr Seaward added.

The command centre was swamped with more calls seeking survival guidance than in the previous 10 years for the whole of London combined, the inquiry heard.

Dozens of firefighters are expected to give evidence at the probe, leading the LFB lawyer to warn chairman Sir Martin Moore-Bick of their potentially fragile state of mind.

Mr Seaward questioned whether, given "multiple" safety failings within the building, "the firefighters were always chasing a sinister fire they had no realistic chance of defeating".

It has been almost one year since 72 people were killed in the fire (Image: PA)

He said Sir Martin should consider whether early incident commanders had training and procedures on issues such as tackling cladding fires, looking out for signs of a breach of compartmentation and when to abandon a stay-put policy.

"We submit on the evidence so far that there were no such procedures, nor had firefighters received any such training."

He added of the challenges faced that night: "The FBU invites you to consider whether the firefighters were put in an impossible situation."

It was heard many rescuers faced tough choices which had "serious consequences" regardless of the outcome.

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Mr Walsh QC said: "The LFB believes the scale, the sheer scale, of failures at Grenfell Tower and sheer scale of the fire that resulted from them was a combination of factors that, taken together, created a unique and unprecedented set of challenges for the fire service nationally."

He said firefighters responding to the blaze that night would have been "wholly unaware of the defects in the fabric on the building".

He echoed concerns that criticisms have been made of their strategy with the "benefit of hindsight".

Both the LFB and the FBU flatly denied claims made on Tuesday that firefighters could have been guilty of unconscious racism as they tackled the blaze.

The claim was made by lawyer for bereaved and survivors Imran Khan QC, who cited the "stereotypes" used in firefighters' descriptions of residents from black or minority backgrounds.

The Grenfell Tower inquiry team believes it "may very well be possible" for "urgent, interim recommendations" to be made ahead of the publication of Sir Martin's first report, the inquiry heard.

Counsel to the inquiry Richard Millett QC said in his closing remarks that there was a "broad measure of agreement" among core participants for the move.

It followed calls from several parties involved in the probe that important safety recommendations be made as soon as possible.

Meanwhile, police have announced nine people have been arrested over allegations of fraud in connection with the fire.

Officers raided 11 addresses, predominantly in west London, at around 7am on Thursday.

A tribute hangs from a hoarding surrounding the tower (Image: REUTERS)

Mr Bonner said: "All those arrests are in connection with what we believe to be fraudulent claims for housing and/or support of one kind or another, arising out of false claims from people that they were associated with Grenfell Tower."

Regarding the timing of the arrests, he added: "We thought long and hard, there's obviously a need for us to act quickly once we are able to but also wanted to show due respect to events that have been going on in recent weeks in terms of the commemoration hearings and events that are forthcoming in terms of the anniversary.

"We have consulted with the community where we could and we timed them with utmost respect to all considerations."

In response to the arrests, Shahin Sadafi, chair of Grenfell United said: "It is hurtful and saddening that people would take advantage of a tragedy like this.

"It is not just that they have taken funds and charity that was not for them, it is disrespectful to the real victims of the fire and people who lost their lives.

"Our community has shown strength, determination and dignity throughout the last year. Grenfell Tower was a community of good decent people, and we were proud to be each others' neighbours.

"These people have absolutely no place here. We are relieved they have been identified and rooted out."